There was one piece of realism which the Greeks were not averse to, and that was the presence of horses and chariots in the theatre. We have already referred to the instances in tragedy where persons from a distance arrive in chariots drawn by horses or mules. The vast size of the Greek theatre made it peculiarly suitable for displays of this character. In the Agamemnon of Aeschylus, Agamemnon and Cassandra approach the palace in a chariot; Agamemnon remains seated there for a considerable time, while he converses with Clytaemnestra; he then dismounts and enters the palace, leaving Cassandra still in the chariot. In the Electra of Euripides, when Clytaemnestra comes to visit her daughter at the country cottage, she arrives in a chariot, accompanied by Trojan maidens, who assist her to dismount.[619] Animals for riding were also occasionally introduced. In the Prometheus there is the winged steed upon which Oceanus makes his entrance; and in the Frogs of Aristophanes Xanthias rides in upon a donkey.[620] § 6. _The Ekkyklema._ Several mechanical contrivances are mentioned in connexion with the Greek stage. The most peculiar of these, and the one most alien to all our modern notions of stage illusion, is the ekkyklema.[621] We have seen that in a Greek theatre the action always took place in the open air, before some temple or dwelling-place. It was impossible to transfer the scene to the inside of the building because of the continual presence of the chorus in the orchestra. Still, it might sometimes happen that a powerful dramatic effect could be produced, if a deed accomplished indoors was exposed to view. The most natural way of doing this would have been to draw aside the back-scene, and reveal a portion of the interior. But in the Greek theatre, owing to the narrowness of the stage-buildings, such a device was hardly practicable. Even if the stage-buildings had been made deeper, there were obvious objections in the way. The relative position of the auditorium and the stage was such that, if a room had been opened out behind the back-scene, a large part of the audience would not have been able to see into it. In any case, the back part of the room would have been almost in the dark. Further than this, the whole arrangement was far too elaborate for the simple notions of the ancient stage-managers. For these reasons a more primitive device was adopted. Scenes inside the house or palace were revealed by means of the ekkyklema. This was a small wooden platform, rolling upon wheels, which was kept inside the stage-buildings. When it was required to be used, one of the doors in the background was thrown open, and it was pushed forward on to the stage. Upon it was arranged a group of figures, representing in a sort of tableau the deed or occurrence which had just taken place inside the building. It was mostly used in cases where a murder had been committed. The ekkyklema was rolled out upon